There is a rapidly growing need to process large amounts of data in real-time in such areas as telecommunications, finance, etc. For example, in customer contact centers, agent-groups can be large, each divided into several subsets of agents with statistics being acquired for each subset and then aggregated for the entire agent group. The statistics across multiple subsets of agents may need to be continuously tracked and updated. This real-time computing processing can present challenges to system designers, for example, in providing up-to-the minute statistical data that is both timely and accurate.